Revert "Remove NonCompositedContentHost" and follow-up rebaselining.

Source/core/rendering/RenderLayerBacking.h

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 82 matching lines @@
     
     bool hasScrollingLayer() const { return m_scrollingLayer; }
     GraphicsLayer* scrollingLayer() const { return m_scrollingLayer.get(); }
     GraphicsLayer* scrollingContentsLayer() const { return m_scrollingContentsLayer.get(); }
 
     bool hasMaskLayer() const { return m_maskLayer != 0; }
 
     GraphicsLayer* parentForSublayers() const;
     GraphicsLayer* childForSuperlayers() const;
 
+    // RenderLayers with backing normally short-circuit paintLayer() because
+    // their content is rendered via callbacks from GraphicsLayer. However, the document
+    // layer is special, because it has a GraphicsLayer to act as a container for the GraphicsLayers
+    // for descendants, but its contents usually render into the window (in which case this returns true).
+    // This returns false for other layers, and when the document layer actually needs to paint into its backing store
+    // for some reason.
+    bool paintsIntoWindow() const;
+    
     // Returns true for a composited layer that has no backing store of its own, so
     // paints into some ancestor layer.
     bool paintsIntoCompositedAncestor() const { return !m_requiresOwnBackingStore; }
 
     void setRequiresOwnBackingStore(bool);
 
     void setContentsNeedDisplay();
     // r is in the coordinate space of the layer's render object
     void setContentsNeedDisplayInRect(const IntRect&);
 
@@ skipping 146 matching lines @@
     bool m_boundsConstrainedByClipping;
     bool m_isMainFrameRenderViewLayer;
     bool m_requiresOwnBackingStore;
     bool m_canCompositeFilters;
     bool m_backgroundLayerPaintsFixedRootBackground;
 };
 
 } // namespace WebCore
 
 #endif // RenderLayerBacking_h